Turdus migratorius

Geographic Range

American robins are native to the Nearctic region. They occur year-round in southern Canada from Newfoundland to British Columbia, throughout most of the United States and along the Sierra Madre into southern Mexico. They migrate south for the winter, going as far as southern Mexico and Guatemala. In summer they are found as far north as northernmost Canada and Alaska. American robins are the most abundant and widespread North American thrush.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

American robins occur mainly in woodlands, gardens, orchards, lawns, and fields. They prefer areas of open ground or short grass for foraging, with woodland or a few scattered trees and shrubs nearby for nesting and roosting. Suburban and agricultural areas often provide these kinds of habitats so American robins are common near humans. They need dense shrubs and small trees in which to build their nests. They build nests deep in dense foliage to protect their young from predators.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• scrub forest scrub forest

• Other Habitat Features
• urban urban
• suburban suburban
• agricultural agricultural
• riparian riparian

Physical Description

American robins are birds that measure 25 cm in length and average 77 g in weight. Males are only slightly larger than females. They are brown on their backs, reddish on the breast, and white on their lower belly and under their tail feathers. Their throats are white, streaked with black. They have white crescents above and below their eyes. Females are slightly paler in color than males. Young American robins have dark spots on their breasts and are also paler in color than adult males.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male more colorful

Reproduction

Males and females form a pair bond during breeding season and while raising their young.

• Mating System
• monogamous monogamous

American robins breed in the spring shortly after returning to their summer range (north) from their winter range (south). The breeding season extends from April through July. American robins are one of the first birds to begin laying eggs and normally have two or three sets of young, or broods, in each breeding season. The cup-shaped nest is built by the female, who builds the outer foundation with long coarse grass, twigs, paper, and feathers woven together. She lines the inner bowl with mud, smearing it with her breast and later adding fine grass or other soft material to cushion the eggs. The nest can be located on the ground or high up in trees, but most commonly 5 to 15 feet above ground in a dense bush, in the crotch of trees, or on window ledges or other human structures. All that is needed for the nest is a firm support and protection from rain. A new nest is built to raise each brood. In northern areas the first clutch is generally placed in an evergreen tree or shrub, and the later clutches are laid in a deciduous tree. From 3 to 5 eggs are laid in each clutch.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Eggs are incubated by the female. After about 14 days of incubation the eggs hatch. She continues to feed and brood the chicks while they are very young. When the nestlings become older the female broods them only at night or during bad weather. Baby birds leave the nest about 2 weeks after they have hatched. All babies from a clutch leave the nest within 1 day of each other. Even after leaving the nest, the young birds follow their parents and beg food from them. They remain under cover on the ground during this time. About two weeks after fledging, young American robins become capable of sustained flight.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female

Lifespan/Longevity

One wild bird lived to be almost 14 years old, though most American robins in the wild will live about 2 years. Only about one quarter of all young American robins will survive the summer in which they were born.

Behavior

American robins are active mostly during the day. They are social birds, especially during the winter when they are gathered in large numbers on their winter grounds. They assemble in large flocks at night, often in a secluded swamp or area of dense vegetation, where they roost in the trees. These winter aggregations break up during the day to feed in smaller flocks on fruits and berries. American robins defend breeding territories during the summer and are less social during that time. Young American robins remain in the area of their nest for their first 4 months of life. They gather in mixed-age flocks when it becomes time to depart for their winter grounds. Almost all populations of American robins are migratory.

• Key Behaviors
• flies
• diurnal diurnal
• motile motile
• migratory migratory
• social social

Communication and Perception

Soon after hatching nestlings begin to beg for food by chirping. Adult American robins use chirping or chucking to warn of the presence of a predator. Males begin to sing in the late winter and early spring. This song is a familiar sound in the springtime and sounds something like 'cheerily, cheer up, cheer up, cheerily, cheer up.' American robins sing frequently throughout the day, but particularly early in the morning. They most often sing from a perching spot high in a tree.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

American Robins feed on a mixture of both wild and cultivated fruits, berries, earthworms , and insects such as beetle grubs, caterpillars , and grasshoppers . Robins are flexible and will turn to whichever food is most readily accessible, although the diet generally consists of approximately 40% invertebrates, 60% fruits and berries.

• Primary Diet
• omnivore omnivore

• Animal Foods
• eggs
• insects
• terrestrial non-insect arthropods
• terrestrial worms

• Plant Foods
• fruit

Predation

American robins may mob small predators, such as blue jays and snakes . They also produce chirping and chucking sounds as warning calls.

Predators on young and adults differ somewhat. Eggs and young are often eaten by different types of squirrels , snakes , and birds such as blue jays , common grackles , American crows , and common ravens . Adult American robins are preyed upon by hawks , cats , and larger snakes .

American robins are vigilant when feeding, they may feed in loose flocks, so that they can also watch other robins for reactions to predators.

Ecosystem Roles

American robins are important as prey items to their predators because there are so many of them. They also act to control some insect populations and to disperse the seeds of the fruits they eat.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

American robins are effective in controlling insects that may damage crops and gardens, such as beetles.

• Positive Impacts
• controls pest population

Economic Importance for Humans: Negative

Part of the American robin's diet may include berries, which can reduce the number of berries harvested every year by cultivators. It has also been reported that male American robins have pecked at and damaged windowpanes, windshields, hubcaps, and other polished surfaces, apparently reacting to their own reflections.

• Negative Impacts
• crop pest

Conservation Status

American robins are successful birds, having been able to adapt to human alteration of the landscape. At one time, they were killed for meat in some southern States, and the meat was considered a delicacy. They are now protected throughout their range by the U.S. Migratory Bird Protection Act.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Tanya Dewey (author, editor), Animal Diversity Web.

Candice Middlebrook (author), University of Michigan-Ann Arbor.

References

Sallabanks, R., R. James. 1999. American Robin (Turdus migratorius). Birds of North America , 462: 1-20.

Pough, Richard H. 1946. Audubon Land Bird Guide. Doubleday and Company, New York.

Burton M. and Bruton R. 1980. The New Funk and Wagnalls Illustrated wildlife Encyclopedia, BPC Publishing Limited, 1:91-92.

Burke, Ken. 1983. How to Attract Birds. Orhtho Books, San Francisco.